This Vintage style 1867 Confederation baseboard is a common profile in older homes. Sometimes it is placed on top of a piece of dimensional to add height.  There is a 7-1/4" tall version in stock as well.

Baseboard ties the wall and floor together offering a visual foundation. It protects the walls from bumps and cleaning. The baseboard should compliment the style of casing and should be thinner and wider than the casing. Shoe mould often accompanies the baseboard if the floor is uneven or there is gaps between the baseboard and the flooring.